This invention relates in general to imaging belts and, more specifically, to a method for making a flexible belt.
Flexible imaging belts include, for example, electrophotographic imaging belts or photoreceptors for electrophotographic imaging systems, ionographic imaging belts or electroreceptors for electrographic imaging systems, and intermediate image transfer belts for transferring toner images used in an electrophotographic or an electrographic imaging system.
Flexible electrophotographic imaging belts are usually multilayered photoreceptors that comprise a substrate, an electrically conductive layer, an optional hole blocking layer, an adhesive layer, a charge generating layer, and a charge transport layer and, in some embodiments, an anti-curl backing layer. One type of multilayered photoreceptor comprises a layer of finely divided particles of a photoconductive inorganic compound dispersed in an electrically insulating organic resin binder. A layered photoreceptor having separate charge generating (photogenerating) and charge transport layers is described in U.S. Pat. No. 4,265,990.
The flexible electrophotographic imaging belts may be fabricated from a sheet cut from an imaging member web. The sheets are generally rectangular or parallelogram in shape. All edges may be of the same length or one pair of parallel edges may be longer than the other pair of parallel edges. The sheets are formed into a belt by joining the overlapping opposite marginal end regions of the sheet. A seam may be produced in the overlapping marginal end regions at the point of joining. Joining may be effected by any suitable means. Joining techniques include welding (including ultrasonic), gluing, taping, pressure heat fusing, and the like. However, ultrasonic welding is generally the chosen method for flexible imaging member seam joining because it is rapid, clean (no solvents), produces a thin and narrow seam, and a low cost seaming technique. In addition, ultrasonic welding is preferred because the mechanical pounding of the welding horn causes generation of heat at the contiguous overlapping end marginal regions of the sheet to maximize melting of one or more layers therein to form a strong seam joint. The ultrasonic welding process is carried out by holding down the overlapped ends of a flexible imaging member sheet with vacuum against a flat anvil surface and guiding the flat end of an ultrasonic vibrating horn transversely across the width of the sheet, over and along the length of the overlapped ends, to form a welded seam.
When ultrasonically welded into a belt, the seam of flexible multilayered electrophotographic imaging member belts may occasionally contain undesirable high protrusions such as peaks, ridges, spikes, and is mounds. These seam protrusion spots may present problems during image cycling of the belt in the machine because they interact with cleaning blades which may affect cleaning blade efficiency and service life. Moreover, the protrusion high spots in the seam may also interfere with the operation of subsystems of copiers, printers and duplicators.
Imaging belts are manually inspected after seam welding by passing a cotton glove over the entire seam length and belts found catching the glove by the protrusions are identified as production rejects. Both the time consuming procedure of manual inspection and the number of seamed belts rejected due to the presence of high seam protrusions constitute a substantial financial burden on the production cost of imaging member belts.
Referring now to FIGS. 1-3, there is shown a prior art system 20 used for making an imaging belt 10. The imaging belt 10 is flexible and includes an outside photosensitive surface A, and an inside surface B. The ends of the belt overlap and are joined by an ultrasonic welding process. The welded seam shown includes a surface roughness on the photosensitive surface A comprising a high protrusion spike 40. The photosensitive side A is welded directly with the contact surface 23 of the ultrasonic welding horn 22 from the outside of the belt 10 toward the inside of the belt. The work surface 24 is in contact with side B.
The welding horn is traversed across the photoconductive material, surface A, causing weld splash to protrude out the top and bottom sides of the seam overlap. This material may comprise all of the coated layers along with some of the substrate material. The mechanical energy of the vibrating horn is transferred into the overlapped material creating heat and pressure, which in turn bonds the two ends together. During this welding process, molten material is squeezed from between the joined edges and flows both out the top and bottom side of the welded seam. This material is commonly referred to as xe2x80x9cweld splashxe2x80x9d. Smoothing out this weld splash area would improve performance and maintenance issues.
Therefore, there is a need to provide an improved flexible imaging belts for improved performance and which is generally free of protrusion spots on a selected surface such as a photosensitive surface.
Reference is made to imaging belts and belt systems in U.S. Pat. Nos. 6,336,982; 5,552,005; 4,883,742; and 4,265,990.
All documents cited herein, including the foregoing, are incorporated herein by reference in their entireties.
In an embodiment there is provided, a method of forming a belt comprising: providing a flexible member having a length, width and thickness, the flexible member having a first end, second end, and a photosensitive surface; providing a member including a work surface; forming the flexible member in a loop shape such that the first end overlaps the second end and forms an overlap region for a selected distance, the photosensitive surface is on the outside of the loop shape, and one of the first end and the second end are positioned on the photosensitive surface; positioning the overlap region of the flexible member in pressure contact with the work surface such that the photosensitive surface is on the outside of the loop shape; positioning a welding toot on an inside surface of the loop shape of the flexible member opposite the overlap region; and ultrasonically welding the flexible member at one or more locations along the overlap region forming a photoreceptor belt.
In another embodiment there is provided, a method of forming a belt comprising: providing a flexible member having a length, width and thickness, the member having a first end, second end, and a photosensitive surface; forming the flexible member in a loop shape such that the first end overlaps the second end and forms an overlap region for a selected distance, the photosensitive surface is on the outside of the loop shape; positioning the overlap region and the photosensitive surface of the member in pressure contact with a work surface such that the photosensitive surface is on the outside of the loop shape; and ultrasonically welding the member at one or more locations along the overlap region.
In a further embodiment there is provided, a method of forming a photoreceptor belt comprising: providing a flexible member having a length, width and thickness, the member having a first end, second end, and a photosensitive surface; forming the flexible member in a loop shape such that the first end overlaps the second end and forms an overlap region for a selected distance, the photosensitive surface is on the outside of the loop shape; positioning the overlap region of the member in pressure contact with a work surface such that the photosensitive surface is on the outside of the loop shape; and ultrasonically welding the flexible member at one or more locations along the overlap region using an ultrasonic horn directed toward the work surface and the overlap region from the inside of the loop.
In yet another embodiment there is provided, a method of forming a belt comprising: providing a flexible member having a length, width and thickness, the member having a first end, second end, and a photosensitive surface; forming the flexible member in a loop shape such that the first end overlaps the second end and forms an overlap region for a selected distance, the photosensitive surface is on the inside of the loop shape; positioning the overlap region of the member in pressure contact with a work surface such that the photosensitive surface is on the inside of the loop shape; ultrasonically welding the flexible member at one or more locations along the overlap region using an ultrasonic horn; and turning the flexible member inside out after welding such that the photosensitive surface originally formed on the inside of the loop is on the outside of the loop.
In a further embodiment there is provided, a flexible belt made by the process comprising: providing a flexible member having a length, width and thickness, the member having a first end, second end, and a photosensitive surface; forming the flexible member in a loop shape such that the first end overlaps the second end and forms an overlap region for a selected distance, the photosensitive surface is on the outside of the loop shape, and one of the first end and the second end are positioned on the photosensitive surface; positioning the overlap region and the photosensitive surface of the member in pressure contact with a work surface such that the photosensitive surface is on the outside of the loop shape; and ultrasonically welding the flexible member at one or more locations along the overlap region.
In yet another embodiment there is provided, a method of forming a belt comprising: providing a flexible member having a length, width and thickness, the member having a first end, second end, and a selected surface; providing a member including a work surface, the work surface having a first dimensional area; forming the flexible member in a loop shape such that the first end overlaps the second end and forms an overlap region for a selected distance, the selected surface is on the outside of the loop shape, and one of the first end and the second end are positioned on the selected surface; positioning the overlap region of the flexible member in pressure contact with the work surface such that the selected surface is on the outside of the loop shape, the overlap region having a second dimensional area; positioning a welding tool on an inside surface of the loop shape of the flexible member opposite the overlap region, the welding tool having a contact area having a third dimensional area; and ultrasonically welding the flexible member at one or more locations along the overlap region forming a belt.